Question

A man of mass 60 kg standing on a light weighing machine kept in a box of mass 30 kg. The box is hanging from a pulley fixed to the ceiling through a light rope, the other end of which is held by the man himself. If he manages to keep the box at rest (i) what is the weight sho by the machine ? (ii) what force should the man exert on the rope to get his correct weight on the machine ? (Please explain the FBDs you draw for each body)

Answer 1

See the diagram for the setup and free body diagrams.

All objects and the man are in static equilibrium. So forces are balanced.

Given m1 = 60 kg,    m2 = 30 kg.

For the Box:      m2 g + N2 = T   ---(1)

For the weighing machine:   N2 = N1    --- (2)

For the man:     T = m1 g - N1     ----(3)

Solving these three equations we get:
  
          T = (m1 + m2)/2 * g = (60+30)/2 * g = 45 kg wt or 
=>      T = 450 Newtons approx.  with  g = 10 m/sec^2

           N1 = (m1 - m2)/2 * g = (60-30)/2 * g = 15 kg wt  
                 = 150 Newtons approx.

The weighing machine shows 15 kg as the weight of the man.

Answer 2

Answer:

150 N

Explanation:

the man standing on weighting machine so the weight of man should subtract from weight of box and should divide by 2 ...